SpaceX Grasshopper reaches new Heights making its final Jump

October 13, 2013

YouTube Screenshot - Credit: SpaceX

The SpaceX Grasshopper has made a new record-setting leap on October 7, 2013 at the company's test site, McGregor, Texas. The 744-meter leap was the final test planned for the Grasshopper with low-altitude testing of the Falcon 9 Reusable (F9R) being next.

Powered by a single Merlin 1D engine that provides throttle capability, Grasshopper embarked on its highest jump to date. Unlike the last test that demonstrated a lateral divert, this jump of Grasshopper took the vehicle to an altitude of 744 meters right above its launch & landing platform before the vehicle throttled down and started descending for an on-target landing. Video captured by a remote-controlled Hexacopter shows the Grasshopper up close during its ambitious test.

Grasshopper stands 32.3 meters tall and represents a modified Falcon 9 first stage that is equipped with a steel support structure and features four steel and aluminum landing legs with hydraulic dampeners. Gimbaling the Merlin 1D engine provides vehicle control during the flight.

The Grasshopper testbed successfully demonstrated the low-altitude, low-velocity aspect of returning a Falcon 9 first stage to the launch site to make it fully reusable. Grasshopper allowed SpaceX to develop and refine flight control algorithms for landings with a thrust to weight ratio of more than one which is key for future propulsive Falcon 9 landings.

Falcon 9 lifted off with the Canadian Cassiope satellite and a number of secondary payloads and completed a nominal ascent mission as its nine Merlin 1D first stage engines fired. After the first stage shut down and separated from the second stage, it performed a re-orientation maneuver and conducted a retrograde braking maneuver – burning three of its engines to slow down ahead of re-entering the atmosphere.

The first stage re-entered the atmosphere at high speed and demonstrated that the stage could withstand the aerodynamic environment of entry and maintain a stable flight position. Following re-entry, the first stage was planned to ignite its center engine to make a soft splashdown landing in the Pacific Ocean, downrange from the launch site at Vandenberg Air Force Base. This final burn was cut short when the first stage exhibited an excessive roll that could not be countered by its cold-gas attitude control system and caused leftover propellants to be centrifuged up the tank walls. Following the early shutdown of the engine, the first stage made a crash landing in the ocean.

Even though this first demonstration did not achieve the desired soft splashdown, the test confirmed that the first stage can perform a re-ignition to slow down ahead of entry, survive in the harsh entry environment and put itself into a position to make its final landing maneuver. SpaceX will tweak the sequence to prevent the roll on the first stage during atmospheric flight and achieve a soft landing in the ocean on a subsequent flight.

While testing continues as part of Falcon 9 v1.1 flights, SpaceX has also built its first Flacon 9R first stage with deployable landing legs. Supersonic test flights taking the reusable first stage out of the atmosphere and back to a safe landing on land will be performed at White Sands Missile Range, New Mexico. Before those tests can begin, the F9R stage will perform a number of smaller jumps at McGregor to verify the design and functionality of the vehicle before more ambitious tests are performed.

SpaceX Grasshopper completes first Divert Test

August 14, 2013

The SpaceX Grasshopper completed its first divert test on August 13, 2013 at SpaceX’ Texas Facility. Lifting off powered by its single Merlin 1D engine, the vehicle ascended to an altitude of 250 meters with a 100-meter lateral maneuver. After a short hover at 250 meters, Grasshopper started descending and simultaneously correcting the lateral offset. A slight over-correction occurred which might have been planned to test the vehicle’s capabilities. The vehicle managed to correct that slight offset as well and smoothly touch down where it launched from. Overall, the vehicle appeared very stable throughout the flight. This flight marked the most ambitious Grasshopper flight yet as it tested a more aggressive steering maneuver putting the flight control algorithm through its paces.

YouTube Screenshot - Credit: SpaceX

“Grasshopper is taller than a ten story building, which makes the control problem particularly challenging. Diverts like this are an important part of the trajectory in order to land the rocket precisely back at the launch site after reentering from space at hypersonic velocity,” SpaceX said.

Grasshopper stands 32.3 meters tall and represents a modified Falcon 9 first stage that is equipped with a steel support structure and features four steel and aluminum landing legs with hydraulic dampeners. The vehicle features the standard Liquid Oxygen and Rocket Propellant 1 Tanks of the Falcon 9 which are not completely filled when Grasshopper takes off as it is only propelled by a single engine – as opposed to Falcon 9’s nine Merlin Engines. Grasshopper features a throttlable Merlin 1D engine – notably one of the early design Merlin 1Ds that does not have the maximum thrust of the production M1Ds that will be used on Falcon 9v1.1.Tests like Tuesday’s divert test are starting to push the Grasshopper in its current design to its maximum. SpaceX has been working on a flight-like Grasshopper for some time that would feature the Falcon 9 v1.1 first stage design and fold-up landing legs which would be eventually used on the Falcon 9 launcher to make its first stage reusable.High- altitude tests of Grasshopper v1.1 will be performed at White Sands Missile Range, New Mexico once the vehicle and facilities are ready.

Earlier - Grasshopper 325-meter Test (June 14, 2013)

SpaceX Grasshopper completes Highest Flight yet

April 23, 2012

The SpaceX Grasshopper has successfully flown to 250 meters last week and landed on its landing legs, making this its highest flight yet, SpaceX reported on Monday. The flight took place at the SpaceX Texas Facility where Grasshopper has been completing tests since mid-2012 – performing higher-and-higher jumps on SpaceX’s path to reusability of the Falcon 9 launcher which is one of the biggest goals the company and its founder, Elon Musk, have set for the future. This latest jump is part of a series of test flights to verify the Guidance, Flight and Landing software the vehicle uses. On Friday, the vehicle ignited its engine, ascended to 250 meters and began a short hover before starting a descent followed by a braking maneuver and a pin-point landing in its original launch position. Grasshopper stands 32.3 meters tall and represents a modified Falcon 9 first stage that is equipped with a steel support structure and features four steel and aluminum landing legs with hydraulic dampeners.

*File Image* - Photo: SpaceX

The vehicle features the standard Liquid Oxygen and Rocket Propellant 1 Tanks of the Falcon 9 which are not completely filled when Grasshopper takes of as it is only propelled by a single engine – as opposed to Falcon 9’s nine Merlin Engines. Grasshopper features a throttlable Merlin 1D engine – notably one of the early design Merlin 1Ds that does not have the maximum thrust of the production M1Ds that will be used on Falcon 9v1.1.

Grasshopper made its first hop on September 21, 2012 as a verification of its functionality and the Flight Control Algorithms. That day, the vehicle flew on nearly empty tanks as a risk reduction and performed a 3-second, 1.8-meter jump. On November 1, Grasshopper made its second jump of 5.4 meters as part of an 8-second flight. The third Grasshopper test included a brief hover of the vehicle once reaching 40 meters for a total flight duration of 29 seconds. While hovering, the vehicle constantly adjusts the thrust output of its engine as it gets lighter and lighter. Merlin 1D gimbaling is used to balance the vehicle and keep it stable. On the way back down, thrust is reduced before braking to bring the vehicle back for a gentle vertical landing – increasing the velocity of the descent and the efficiency of the braking maneuver ahead of touchdown are important elements of flight that are being tested.

The fourth flight of Grasshopper took the vehicle to 80.1 meters. The March 7, 2013 flight was 34 seconds long and again included a short hover segment.

Friday’s flight got to an altitude of 250 meters and had the vehicle lean against the wind to maintain its position above the pad. It demonstrated that the vehicle can land with a thrust to weight ratio of more than 1 which is key for future propulsive Falcon 9 landings.

With Friday’s flight setting a new record, SpaceX is gathering valuable data on hard- and software involved in a vertical takeoff, vertical landing (VTVL) rocket. SpaceX will continue flying this Grasshopper in Texas as part of low-altitude, low-velocity tests with flights of up to 3,500 meters and durations of 160 seconds. The company has already requested FAA approval for a limited amount of flights to higher altitudes.

*File Image* - Photo: SpaceX

Supersonic Flights taking Grasshopper out of the atmosphere will be performed using an upgraded version of the vehicle flying out of White Sands Missile Range, New Mexico. Grasshopper v1.1 will be based on the stretched first stage of the Falcon 9 v1.1 and feature flight-like landing legs that fold-up for launch and flight. This vehicle would fly to out of the dense atmosphere up to altitudes of 90 Kilometers and come back for a propulsive landing.

These flights will feature an engine shutdown once reaching a certain speed followed by a free fall back to Earth and a re-ignition for a propulsive soft landing. This would most likely require Grasshopper v1.1 to be outfitted with an attitude control system, but exact details have not been published by SpaceX yet. The company expected to begin hypersonic flights by the end of the year or early in 2014.

The goal of creating fully re-usable rockets has been on Elon Musk’s mind since the beginning.

Creating such a design would greatly reduce the cost of spaceflight according to Musk. “With each successive test, we want to higher and farther and improve the technology to the point where we'll be doing transitions all the way to hypersonic and back, hopefully later this year," he said.

SpaceX is hard at work testing the individual components and techniques required for a re-usable Falcon 9. The design calls for Falcon 9 taking off from its launch pad, performing a nominal flight delivering the Upper Stage and payload to the expected trajectory at the pre-planned velocity. The stage would then separate and use leftover propellant in its tanks to fly back to the launch site and for a vertical landing. Eventually, SpaceX also desires to make its upper stages re-usable, outfitting them with a heat shield to survive re-entry and perform a soft landing after one orbit around Earth.

Primarily, the company is working on making the first stage re-usable in the next several years. The inauguration of the Falcon 9 v1.1 featuring larger stages and more powerful Merlin 1D engines will mark an important step on the company’s path to re-usability.

On its first flight, currently planned for June, Falcon 9 has excess performance as its payload, the Canadian Cassiope satellite does not require the full performance of the launch vehicle. This enables the vehicle to go through a test after first stage separation using propellants that are still inside the vehicle’s tanks. After separation, the first stage will re-ignite its engine and perform a breaking maneuver to slow down enough so that aerodynamic forces encountered when hitting the atmosphere will not damage the vehicle. After that burn, the stage will fall back to Earth and re-ignite one more time of slow down just before hitting the water to make a soft splashdown.

SpaceX plans to fly a number of instrumented first stages that attempt a such a soft splashdown in 2013 and into 2014. Elon Musk has said that it is not expected that this flight profile will be successful on the first or first few attempts as teams are entering new territory. Fine-tuning of the sequence will implement lessons learned from previous attempts to successfully land 1st stages in the Ocean before the capability of flying back to the launch site is available.

*File Image* - Photo: SpaceX

Earlier Grasshopper Flight Videos

Fourth Flight - 80.1-meter Hoverslam

Third Flight - 40-meter Flight

Second Flight - 5.4-meter Jump

First Flight - 1.8-meter Hop

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